Details: Conversion kit to allow use of 12mm thru axle wheels in a 15mm thru axle fork by the following manufacturers: Niner, GT, Scott, Jamis, Kona, Norco, Felt, Rose, Whisky, TRP, KTM, Genesis, plus others. Kit includes one M15x1.5mm x 15mm long thread adapter with M12x1.5mm threads on the ID plus one 15mm OD x 12 mm ID x 10mm long thru hole insert. Depending on your forks actual dimensions, kit components may need slight trimming so that they do not protrude on the inside of each dropout. THIS IS CRITICAL! This kit is does NOT include an axle. A compatible axle must be purchased separately. Axle must be 12mm OD with an M12x1.5mm thread. Unthreaded length must be no more than 113mm (total length minus threaded length). Axle length should be 125-129mm long. NOTE: This kit does NOT work with forks that have M14x1.5mm threads which includes all TREK 15mm thru axle forks. Please email if unsure if this kit will fit your fork.